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A very coherent picture of the effect of dietary fat in MS development and progression emerges from many papers in reputable medical journals. There is also substantial literature on the distribution of MS world-wide and how it relates to diet, particularly fat consumption. The most important research, however, is the life-long work of Professor Roy Laver Swank of the Swank Multiple Sclerosis Clinic in Portland, Oregon, in the USA.

Professor Swank noted that the incidence of MS seemed to follow the consumption of saturated fat, particularly dairy products, and was lower wherever fish consumption (with its high omega-3 fat content) was high.1 The best summary is from Swank and Dugan’s book, The Multiple Sclerosis Diet Book.2 Here Swank shows how the consumption of fat in Western countries such as the USA has jumped this century. In 1909, people in the US consumed on average 125 grams per day of fat. By 1948 this had risen to 141g. By 1972 this figure had leapt to 150g. In Western Europe the rate of increase was even higher. Worse, the percentage of all calories in the diet in the US coming from fat had jumped in this period to over 40 per cent. This is in comparison to an estimated 15 per cent some 200 years ago. Swank also showed that the daily fat intake in countries correlated with how common MS was.

Professor Swank’s Low Saturated Fat Study

Beginning in 1949, he enrolled 150 MS patients and commenced them on his MS diet, a very low saturated fat diet.3 He followed them with meticulous examination and recording of their dietary fat consumption for 34 years. There was no control group who had normal diets, however many of the patients were unable to stick to the MS diet, allowing comparison between those that did and those that did not. There are also data on relapse rates in MS from many other studies. The study was supported by grants from the MS Society of Canada, the Montreal Neurological Institute, the Department of Health and Welfare of Canada, the MS Society of Portland and other grants. This was a major piece of medical research.

A number of papers resulted from this study, one in one of the world’s premier medical journals, the Lancet in 1990,3 and another in Nutrition in 1991.4 The results provide enormous hope to people with MS.

The paper in the Lancet reported results for 144 patients. Of these, 72 patients were able to stick to the MS diet (good dieters), that is they consumed less than 20g/day of saturated fat. The other 72 could not keep fat consumption below 20g/day. The patients’ neurological disability was graded using a neurological disability scale devised by Swank, which went from 0 (essentially unimpaired) to 6 (deceased). Point 4 on the scale represented wheelchair needed, and point 5 confined to bed and chair. Swank’s scale essentially used 2 points on Kurtzke’s EDSS scale to every 1 point on his.

The results were dramatic. Regardless of level of disability at entry to the trial, good dieters did not deteriorate significantly. Good dieters at level 1 on entry had an average final grade of 1.9 34 years later. Good dieters at level 2 had a final level of 3.6, and those at level 3 or worse a final level of 4. The results were best for those who started with minimum disability, with 95 per cent surviving and still physically active 34 years later, excluding those who died from non-MS diseases. The benefits occurred in all three groups, and even people with significant disability were shown to markedly slow the progression of the disease if they could stick to the MS diet. The picture for poor dieters was terrible, in line with results from other series of MS patients whose conditions have been monitored over time. Poor dieters with minimum disability at entry ended with average grade of 5.3, that is wheelchair and bed bound. Those with moderate disability ended up at 5.3 also, and those with severe disability at 5.6. Only 7 per cent of patients who did not stick to the MS diet remained active. The death rate amongst the poor dieters was extremely high. 58 of the 72 were dead by 34 years, 45 from MS-related causes. The statistics were very strong. The p values were generally of the order of p<0.0001 to <0.0005 for most of the differences between good and poor dieters. That is, the difference was extremely unlikely to have occurred by chance.

Swank noted that patients who adhered to the diet for MS actually consumed 16g of saturated fat per day on average, whereas those who did not adhere to the diet for MS consumed 38g/day. Even for the ‘poor dieters’ this was a marked reduction from the average 125g/day they were consuming prior to the study. It reinforces the message that the MS diet is an all or nothing issue. Just lowering saturated fat consumption, even by two thirds as the poor dieters did, is not enough to make a difference to the progression of the disease. Saturated fat must really be completely avoided if possible.
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Why Has This Been Ignored?

This unique piece of research on diet and MS has been largely ignored. There has only been one major criticism of Swank’s work that I can find published.5 The authors argued that the neurological assessments of the patients, that is determining how they progressed, were not blinded. This means that the investigators knew which patients were sticking to the MS diet when they tested them to see how the disease had progressed. While this may have introduced some bias into the assessment, it is very hard to argue that there is bias in assessing whether someone is bed-bound or confined to a wheelchair (or dead!), as most of the poor dieters were.
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The Damning Editorial

Most journals have a policy of publishing comments on important papers in the same issue. These editorials are designed to give an expert view of where that research fits into the overall scheme of things. The Lancet is one of the premier medical journals in the world. The Lancet, along with the British Medical Journal, Journal of the American Medical Association and New England Journal of Medicine, constitute the ‘Big Four’ medical journals in the world. Their influence on medical thinking is profound. Their editorials are even more influential than the individual research papers, representing as they do elite medical opinion on the scientific value of the paper to which they refer.

The Lancet at the time had a policy, one which in general has been criticised by many other editors, of publishing anonymous editorials. Many journals, such as the Medical Journal of Australia, commission experts to write editorials on papers they publish, but tell the readership who these experts are. In that way, they become accountable for the opinions they espouse, just as the authors of the original papers are. The policy of not identifying the authors of the editorials has been criticised as encouraging unbalanced editorials. Incidentally, the Lancet has since changed its policy and now identifies the authors of such reviews, calling them Commentaries rather than Editorials.

The editorial in the Lancet on Professor Swank’s paper was critical of the study.6 The author, unnamed, criticised the paper for not being randomised; that is the patients were not randomly allocated to low and normal fat in the diet. The editorial author suggested that those patients who relapsed would be more likely not to follow the MS diet. In summing up, this unnamed author wrote ‘the role of lipids in MS must remain not proven’. Carrying with it the impressive and prestigious stamp of the Lancet, this was a powerful message. Must the evidence be absolutely conclusive though? If we are talking about a powerful drug with toxic side effects, we have a duty to be absolutely certain it works before offering it to our patients. But what about a therapy with positive side effects like reduced incidence of heart attack, high blood pressure, depression, and so on, especially if the disease is incurable, and the study results strongly suggest a massive benefit? Even if the therapy didn’t work for MS, surely doctors would be happy to see patients’ general health improving with better diet.

It is ironic to think that the great strength of Swank’s study, that is its duration of 34 years, was also its great weakness. It is rare to find any clinical trials in the medical literature of such duration. The interferon trials in MS for example have typically been of around one to two years’ duration. When Swank started his study in 1949, the standard of proof in medicine was to test a new therapy out on patients and assess whether they got better or not. This must seem a sensible way to assess these things to the average person. Indeed, the 1934 Nobel Prize in Medicine, the first won by an American, went to Dr George Minot for his work on a chopped liver diet in pernicious anaemia. Minot gave his patients the chopped liver diet, followed them for about 9 months, and found that they all did far better than any patients with the disease had previously. People who defaulted on the diet got sick again very quickly.

The parallels with Swank’s work are obvious. But because of the duration of Swank’s study, by the time it was published in 1990, the standard of proof in medicine had changed dramatically. Randomised controlled trials had become the accepted level of evidence. Ironically, this important piece of research on diet and MS potentially could have won Swank a Nobel Prize had it been published at the time he started it; by the time it was finished it was consigned to the ‘unproven’ basket and largely dismissed by a doubting medical profession. This is despite the fact that the disease was considered incurable, at the time had no other therapies which were effective, and the only side effects of treatment with Swank’s diet were positive. And the benefit for people with MS was shown to be dramatic. Curious.

Swank’s diet for MS had a huge advantage over other tried therapies. It was not a therapy like interferon, in which patients passively receive treatment from a medical practitioner. It involved patients actively controlling their illness with a major lifestyle change. The power that such control gives patients should not be underestimated, and may have significant effects as well on their immune function and mental state. That is the reason it forms the centerpiece of the Taking Control Program.
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50 Year Follow Up of Swank’s Patients

Swank continued to follow up the surviving patients of his original study. The most recent publication about these patients provides more insight into the original work.7 The 63 patients surviving at the end of the 34 year study were followed up after a period of 50 years by the time of this review. The great majority of the surviving 63 patients (47) had adhered to the MS diet; there were only 16 survivors who had not adhered to the MS diet. For the next 15 years after the original study, they were not seen by Swank, but he attempted to contact them at the end of this period. 15 patients were able to be contacted, interviewed and evaluated, 13 from Toronto, 1 from Portland, Oregon and 1 from Montreal. All 15 had remained on the low saturated fat MS diet for 50 years. The ages ranged from 72-84. Of the 15, 13 were essentially physically normal and walked without difficulty. The other two required assistance with walking. Swank concluded that if people with MS can rigorously follow the diet, with no more than 10-15g of saturated fat per day, they can expect to ‘survive and be ambulant and otherwise normal to an advanced age’.

An editorial on this follow up study by Swank in the same journal provided a biochemical explanation of why the diet for MS should work.8 It concluded with the intriguing question: ‘The big question is: If their results are so stunningly impressive, why haven’t other physicians, neurologists, or centers adopted this method of treatment?’ That is a big question indeed.
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Other Studies

A number of other studies on low saturated fat diets in MS have been published. Published in 1984, written in French, and translated into Italian, German and Spanish, but not English, Dr Kousmine’s book, ‘Multiple Sclerosis is Curable’ outlines 55 cases she treated over a period of 19-26 years. She treated the patients with a diet for MS very similar to Professor Swank’s, and supplemented with 1-2 tablespoons of cold pressed oil (sunflower, linseed or wheatgerm), and gave them a cream substitute made from linseed oil.

Like Swank’s patients, they did remarkably well, with most stabilising their condition, and a number improving. Of the 55 patients, 20 had progressive forms of MS and the rest relapsing-remitting. Eight dropped out after stopping the diet, but of those who stayed in the study, only one deteriorated due to MS, while four developed cancer and one scleroderma. In most cases response to the diet was very good. Again, it is unusual to find studies of such duration in medical research, and we would be unwise to ignore the findings, even though the study was not a randomised controlled trial. Dr Kousmine trained initially in science, then in medicine and specialised in paediatrics.

She wrote another book entitled ‘Be and Stay Well Until 80 or More’, in which she outlined her views on the damage caused by typical high saturated fat and processed food Western diets. Much of this is of course now accepted by the medical profession, but her views were strongly criticised at the time by her colleagues. Dr Kousmine herself lived to the age of 88. Just to show how much in medicine is old news being re-discovered, researchers from Norway have recently shown that a low saturated fat diet plus omega-3 supplementation was helpful in a group of patients with MS, and suggested this area needs more formal study!9

In 2005, the first RCT on dietary fat in MS was published.10 This was unfortunately only a small study of limited duration but is an important addition to the evidence base on dietary fats in MS. In a one year study, 31 patients with relapsing-remitting MS were assigned to a low fat diet (15% of calories) supplemented with fish oil or the standard American Heart Association heart diet in which fat made up 30% of calories, supplemented with olive oil. Unfortunately this was a relatively short study. The maximal benefit of diet in Swank’s study did not occur until at least the three year mark. Secondly, the fat reduction was not specifically directed at saturated fat, and both groups lowered their fat intake. Lastly, olive oil is likely to have some benefit based on animal work in experimental MS.

Despite these issues, the study showed that patients felt better according to standard MS quality of life questionnaires. But more importantly, their relapse rates fell quite significantly from pre-trial rates, more so for the fish oil group who had about 0.8 relapses/year less versus 0.7 for the olive oil group. These findings were statistically significant despite the small numbers of participants. The MS community is crying out for more well-designed research in the area, and researchers have speculated that with more research, diet may well become standard treatment in the future.11
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Support for a Low Saturated Fat Diet from Basic Science

Scientists at the Hormel Institute and the Mayo Clinic in Minnesota looked at the fatty acid composition of plasma in 14 patients with MS and compared this with 100 patients without MS.12 The cells of MS patients were comprised of significantly less polyunsaturated fatty acids than those of people without MS. More importantly, these fats had been replaced in the cells by saturated fatty acids. Two other studies have replicated the findings,13,14 yet there has been little further research in the area. Here we have another possible explanation of why a diet for MS that is rich in polyunsaturates and markedly restricted in saturated fats might improve the condition of people with MS.
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The evidence is extremely convincing. Dietary fats play a major part in the development and progression of MS. Manipulating the intake of fats has a great effect on outcome. The most important part of this equation is to dramatically cut down saturated fats from all sources. The fat story is likely to get even more interesting as knowledge increases. Evidence is starting to emerge that polyunsaturated fatty acids play an important protective role in the CNS,15,16 and some researchers in the field are starting to call for a re-appraisal of the role of fats in the development of MS.17 In a few years, we may see an acceptance of the role of fats in neurological disease just as we have in heart disease. Scientists are now proposing that vegan diets with additional fish oil (plus vitamin D supplementation), through their immune system effects, can be used to prevent the onset of MS in susceptible people.18
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  1. Swank RL. Multiple sclerosis: a correlation of its incidence with dietary fat. Am J Med Sci 1950; 220:421-430.
  2. Swank RL, Dugan BB. The multiple sclerosis diet book. A low fat diet for the treatment of MS. New York: Doubleday, 1987
  3. Swank RL, Dugan BB. Effect of low saturated fat diet in early and late cases of multiple sclerosis. Lancet 1990; 336:37-39
  4. Swank RL. Multiple sclerosis: fat-oil relationship. Nutrition 1991; 7:368-376
  5. Ben-Shlomo Y, Davey Smith G, Marmot MG. Dietary fat in the epidemiology of multiple sclerosis: has the situation been adequately assessed? Neuroepidemiology 1992; 11:214-225.
  6. Anonymous. Lipids and multiple sclerosis. Lancet 1990; 336:25-26
  7. Swank RL, Goodwin J. Review of MS patient survival on a Swank low saturated fat diet. Nutrition 2003; 19:161-162
  8. Das UN. Is there a role for saturated and long-chain fatty acids in multiple sclerosis? Nutrition 2003; 19:163-166
  9. Nordvik I, Myhr KM, Nyland H, et al. Effect of dietary advice and n-3 supplementation in newly diagnosed MS patients. Acta Neurol Scand 2000; 102:143-149.
  10. Weinstock-Guttman B, Baier M, Park Y, et al. Low fat dietary intervention with omega-3 fatty acid supplementation in multiple sclerosis patients. Prostaglandins Leukot Essent Fatty Acids 2005
  11. Schwarz S, Leweling H. Multiple sclerosis and nutrition. Mult Scler 2005; 11:24-32
  12. Holman RT, Johnson SB, Kokmen E. Deficiencies of polyunsaturated fatty acids and replacement by nonessential fatty acids in plasma lipids in multiple sclerosis. Proc Natl Acad Sci USA 1989; 86:4720-4724
  13. Nightingale S, Woo E, Smith AD, et al. Red blood cell and adipose tissue fatty acids in mild inactive multiple sclerosis. Acta Neurol Scand 1990; 82:43-50
  14. Cunnane SC, Ho SY, Dore-Duffy P, et al. Essential fatty acid and lipid profiles in plasma and erythrocytes in patients with multiple sclerosis. Am J Clin Nutr 1989; 50:801-806
  15. Lauritzen I, Blondeau N, Heurteaux C, et al. Polyunsaturated fatty acids are potent neuroprotectors. Eur Mol Biol Org J 2000; 19:1784-1793
  16. Blondeau N, Widmann C, Lazdunski M, et al. Polyunsaturated fatty acids induce ischemic and epileptic tolerance. Neuroscience 2002; 109:231-241
  17. Mayer M. Essential fatty acids and related molecular and cellular mechanisms in multiple sclerosis: a new look at old concepts. Folia Biologica (Praha) 1999; 45:133-141
  18. McCarty MF. Upregulation of lymphocyte apoptosis as a strategy for preventing and treating autoimmune disorders: a role for whole-food vegan diets, fish oil and dopamine agonists. Med Hypotheses 2001; 57:258-275.